Apparatus for and method of etching and cleaning objects

ABSTRACT

The invention provides method of etching and cleaning objects contained in a vessel, including: etching the objects by providing etching solution into the vessel; exiting the etching solution from the vessel by providing pressurized gas into the vessel; cleaning the objects by providing cleaning solution into the vessel; and draining the cleaning solution from the vessel. By exiting the etching with pressurized gas such as nitrogen gas, there is no density difference of the etching solution through out the objects, leading to uniform etching of the objects.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the invention

[0002] The present invention relates to etching and cleaning apparatusand method for objects, and more particularly, to apparatus and methodfor batch processes for objects such as a semiconductor wafer or aliquid crystal display (LCD) substrate.

[0003] 2. Description of Related Art

[0004] Etching technology is very important for compact and complicatedsubstrates and is followed by a cleaning process.

[0005] For wet etching process a batch type is usually adopted since itcan provide mass production and low production cost.

[0006]FIG. 1 schematically shows an etching apparatus of batch typeaccording to a conventional art.

[0007] A vessel 10 containing substrates 12 has upper and lower openings111 and 113 and is linked by many pipes. To the upper opening 111 arelinked a first supplying pipe 10 a and a first draining pipe 10 d and tothe lower opening 113 are linked a second supplying pipe 10 b, a thirdsupplying pipe 10 c and a second draining pipe 10 e. The first supplyingpipe 10 a is for supplying IPA(isoprophyl alcohol), the second supplyingpipe 10 b for supplying etching solution, and the third supplying pipe10 c for supplying D.I. (deionized) water. The first draining pipe 10 dis for draining etching solution and D.I. water, and the second drainingpipe 10 e is for draining IPA and D.I. water.

[0008] The etching process and rinsing process using the apparatus isexplained. First, through the second and the third supplying pipes 10 band 10 c, etching solution and D.I. water are supplied to the vessel 10containing substrates 12, respectively. In some conditions only etchingsolution can be supplied, since D.I. water is for diluting the etchingsolution at this time.

[0009] Next, the substrates 12 are etched by the etching solution forsome time.

[0010] Next, D.I. water is supplied through the third supplying pipe 10c so as to pull the mixture of etching solution and D.I. water to theupper opening 111 for draining through the first draining pipe 10 d. Atthis time D.I. water cleans the substrates 12.

[0011] Finally, D.I. water is drained through the second draining pipe10 e and IPA is supplied to the vessel 10 in order to dry the substrates12.

[0012] By the way, referring to FIG. 2, during draining the etchingsolution densities of the etching solution differ depending on thelocation of the interface of the etching solution and the D.I. water forcleaning. That is, in a certain instant during that process the densityis high at the upper portion 12 a of the vessel 10 and low at the middleportion 12 b of the vessel, whereas at the lower portion 12 c of thevessel 10 cleaning water such as D.I. water is filled. This densitydifference results in non-uniform etching of the substrate 12 dependingon the position of the substrate 12.

[0013] And during that time, while etching solution of high density ismixed with D.I. water for cleaning, an abnormal reaction such aselectric reaction occurs. When two metal layers on the substrate areetched at one process, some metals such as aluminum lose their electronsand some metals such as titanium get the electrons. Donor metal is overetched, and the donee is less etched, which deteriorates the quality ofetching.

SUMMARY OF THE INVENTION

[0014] To overcome the problems described above preferred embodiments ofthe present invention provide an apparatus for and a method of etchingand cleaning objects which can achieve uniform etching.

[0015] A preferred embodiment of the present invention provides anapparatus for etching and cleaning objects, including: a vessel having aupper opening and a lower opening; a first supplying pipe connected tothe upper opening of the vessel, the first supplying pipe supplying drygas; a second supplying pipe connected to the lower opening of thevessel, the second supplying pipe supplying etching solution; a thirdsupplying pipe connected to the lower opening of the vessel, the thirdsupplying pipe supplying cleaning solution; a first draining pipeconnected to the upper opening of the vessel, the first draining pipedraining the cleaning solution; and a second draining pipe connected tothe lower opening of the vessel, the second draining pipe draining theetching solution and the dry gas.

[0016] It is preferred that the second draining pipe is directly andstraightly connected to the lower opening of the vessel and has an innerdiameter bigger than other pipes.

[0017] It is also preferred that in the second draining pipe a pump fordraining etching solution is equipped.

[0018] According to another aspect of the invention, the method ofetching and cleaning objects contained in a vessel, including: etchingthe objects by providing etching solution into the vessel; exiting theetching solution from the vessel by providing pressurized gas into thevessel; cleaning the objects by providing cleaning solution into thevessel; and draining the cleaning solution from the vessel.

[0019] Draining the cleaning solution and exiting etching solution areprocessed through different draining pipes connected to the vessel.

[0020] The pressurized gas is preferably nitrogen gas.

[0021] The etching solution is preferably Oxalic acid solution ordiluted Oxalic acid solution.

[0022] The cleaning solution is preferably deionized water.

[0023] Exiting the etching solution is preferably done with pumping theetching solution out of the vessel.

[0024] The method may further include drying the objects by providingdry gas into the vessel after draining the cleaning solution. The drygas may include IPA.

[0025] Advantages of the present invention will become more apparentfrom the detailed description given hereinafter. However, it should beunderstood that the detailed description and specific examples, whileindicating preferred embodiments of the invention, are given by way ofillustration only, since various changes and modifications within thespirit and scope of the invention will become apparent to those skilledin the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For a more complete understanding of the present invention andthe advantages thereof, reference is now made to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich like reference numerals denote like parts, and in which:

[0027]FIG. 1 is a schematic view of an apparatus for etching andcleaning objects according to a conventional art;

[0028]FIG. 2 is a similar view to FIG. 1, illustrating densitydifference in the vessel during the cleaning process while using theapparatus of FIG. 1; and

[0029]FIG. 3 is a schematic view of an apparatus for etching andcleaning objects according to an embodiment of the invention.

DETAILED DESCRIPTION OF PREFFERED EMBODIMENTS

[0030] Reference will now be made in detail to preferred embodiments ofthe present invention, example of which is illustrated in theaccompanying drawings.

[0031] A preferred embodiment of the present invention relates to abatch type apparatus for etching and cleaning the objects such assemiconductor wafers or substrates for LCDs.

[0032] The apparatus shown in FIG. 3 has a vessel 10 having upper andlower openings 110 and 112, which are connected to various pipes. Thepipes connected to the upper opening 110 are a first supplying pipe 10 aand a first draining pipe 10 d, and the pipes connected to the loweropening 112 are second and third supplying pipes 10 b and 10 c and asecond draining pipe 20. Though not illustrated in the drawings, thereare valves in the pipes for selectively closing the pipes.

[0033] The first supplying pipe 10 a is directly connected to the upperopening 110 of the vessel 10, and the first draining pipe 10 d branchesoff from the main passage from the upper opening 110. The seconddraining pipe 20 is preferably straightly connected to the lower opening112 of the vessel 10, and the second and third supplying pipes 10 b and10 c branch off from the main passage from the lower opening 112 of thevessel 10. Since the second draining pipe 20 is straightly connected tothe lower opening 112 of the vessel 10, draining through the seconddraining pipe 20 can be done without any blottleneck. The seconddraining pipe 20 can have an inner diameter bigger than those of otherpipes, and have a pump “P” in order to help easy draining.

[0034] Through the first supplying pipe 10 a pressurized gas and dry gasare supplied to the vessel 10. The pressurized gas needs to have arelatively low solubility to the etching solution and can be nitrogengas. For dry gas IPA(isoprophyl alcohol) can be used, for dry process ithas a gaseous phase having temperature of about 125???.Through thesecond supplying pipe 10 b etching solution such as oxalic acid issupplied to the vessel 10. Through the third supplying pipe 10 ccleaning solution such as deionized water is supplied to the vessel 10.

[0035] The etching and cleaning process using the apparatus of theembodiment is explained.

[0036] First, through the second supplying pipe 10 b etching solution issupplied to the vessel 10 having objects 12. At this time, in order todilute the etching solution, cleaning solution such as D.I. water can besupplied to the vessel 10 at the same time.

[0037] Next, the objects are introduced under the etching process by theetching solution for a determined time.

[0038] Next, through the first supplying pipe 10 a pressurized gasessuch as nitrogen gas is pushed into the vessel in order to drain or exitthe etching solution or the etching solution mixed with the dilutingsolution through the second draining pipe 20. At this time, the seconddraining pipe 20 is open and the pump “P” is operated for easy draining.The pressurized gas is preferably chosen from the group consist of gaseswhich does not react with the etching solution.

[0039] Next, the cleaning solution, for example D.I. water, is suppliedinto the vessel 10 through the third supplying pipe 10 c in order toclean the objects and drained through the first draining pipe 10 d.

[0040] Next, for dry process, IPA gas is supplied through the firstsupplying pipe 10 a and drained through the second draining pipe 20.

[0041] According to the embodiment of the invention, since the cleaningsolution and the etching solution does not make any interface duringexiting the etching solution, there is no density difference of theetching solution through out the objects during the process, which alsoleads no electrical reaction during the process, leading to uniformetching for objects.

What is claimed is:
 1. An apparatus for etching and cleaning objects,comprising: a vessel having a upper opening and a lower opening; a firstsupplying pipe connected to the upper opening of the vessel, the firstsupplying pipe supplying dry gas; a second supplying pipe connected tothe lower opening of the vessel, the second supplying pipe supplyingetching solution; a third supplying pipe connected to the lower openingof the vessel, the third supplying pipe supplying cleaning solution; afirst draining pipe connected to the upper opening of the vessel, thefirst draining pipe draining the cleaning solution; and a seconddraining pipe connected to the lower opening of the vessel, the seconddraining pipe draining the etching solution and the dry gas.
 2. Theapparatus of claim 1, wherein the second draining pipe is directly andstraightly connected to the lower opening of the vessel and has an innerdiameter bigger than other pipes.
 3. The apparatus of claim 1, whereinthe second draining pipe has a pump for easy draining.
 4. A method ofetching and cleaning objects contained in a vessel, comprising: etchingthe objects by providing etching solution into the vessel; exiting theetching solution from the vessel by providing pressurized gas into thevessel; cleaning the objects by providing cleaning solution into thevessel; and draining the cleaning solution from the vessel.
 5. Themethod of claim 4, wherein draining the cleaning solution and exitingetching solution are processed through different draining pipesconnected to the vessel.
 6. The method of claim 4, wherein thepressurized gas is nitrogen gas.
 7. The method of claim 4, wherein theetching solution is Oxalic acid solution or diluted Oxalic acidsolution.
 8. The method of claim 4, wherein the cleaning solution isdeionized water.
 9. The method of claim 4, wherein exiting the etchingsolution is done with pumping the etching solution out of the vessel.10, The method of claim 4, further comprising, drying the objects byproviding dry gas into the vessel after draining the cleaning solution.11. The method of claim 10, wherein the dry gas includes IPA.